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4-1-4 INSPECTION OF THE FAN
MOTOR
NOTE
When the fan motor fails, the remote controller does
not display any error code.
Usage under that status will lead to insufficient
ventilation. The air supply and exhaust fans should
be checked once every one or two months.
You can make a simple check such as below way.
To check the wind flow, hold a bar of which the end
has a string or other similar lightweight item over
the supply grille and exhaust grille.
5 TROUBLE SHOOTING
5-1 THE FOLLOWING SITUATIONS
ARE NOT MALFUNCTIONS
• Operation does not start.
<Symptom>
"Under centralized control" is displayed on the
remote control and pressing the on/off button
causes the display to blink for a few seconds.
<Cause>
The central device is controlling the unit.
The blinking display indicates that the remote
control cannot be used.
<Symptom>
For the contents of the display, refer to the
instruction manual of the remote controller.
<Cause>
The pre-cooling/pre-heating operation is taking
place.
Operation starts after the pre-cooling/pre-heating
operation is over.
<Symptom>
Immediately after the power is turned on.
<Cause>
The operation is in preparation.
Wait for about 1 minute.
<Symptom>
The unit has been in operation for a long time.
<Cause>
The auto cut-off function was triggered.
Operation starts when the ON/OFF button is pressed
once and pressed again after several tens of seconds.
• Operation stops sometimes.
<Symptom>
"U5" is displayed on the remote control and the
operation stops but then restarts after a few
minutes.
<Cause>
The remote control is intercepting interference
(noise) from electrical appliances other than
the total heat exchanger unit and this prevents
communication between the units, causing them to
stop.
Operation automatically restarts when the
interference goes away.
<Symptom>
While in Automatic mode, operation sometimes
stops but it restarts.
<Cause>
The exhaust fan temporarily stops operation
when the mode is switched between "Total heat
exchange" and "Bypass" modes.
• The unit works even when operation lamp is not
ON.
<Symptom>
The unit sometimes operates even when it is
stopped by pressing the ON/OFF button.
<Cause>
The nighttime free cooling operation and 24-hour
ventilation operation are set to "ON".
Refer to Page 5.
• Operation starts even when the remote control
is not operated.
<Symptom>
Immediately after the power is turned on
<Cause>
Turning on the power and power failure recovery
settings are set to "ON".
8
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